The Analytical and Neuropathology Core provides analytical neurochemistry, gross and microscopic pathology, and tissue, CSF and microdialysate banking for the Program Project. The Specific Aims are: 1.) measure nitrate/nitrite as markers of nitric oxide metabolism in humans and animals following traumatic brain injury (TBI) and in response to erythropoietin (Epo) administration following TBI. 2.) measure Epo and Epo receptor following TBI in humans and animals. 3.) measure biomarkers of inflammation in microdialysate and CSF samples following TBI and in response to Epo therapy. 4.) provide neuropathology support for histopathological analysis of experimental TBI including measurement of contusion volumes, neuronal loss, and antigen expression. 5.) provide tissue and CSF, serum, and microdialysate sample banking for animal and human tissue samples from TBI. 6.) provide analysis of arachidonic acid conversion to epoxygenase products by P450 following TBI in experimental animals. As in previous iterations of the Program Project, the Analytical and Neuropathology Core interacts closely with the major scientific projects and with the other cores.